Extraction,isolation,identification And Antioxidant Activity Of Proanthocyanidins From Chestnut Shell

In this paper,the wild chestnut in Yimeng Mountain of Shandong Province was used as raw material and the effective components of chestnut shell were studied.The composition of chestnut shell were isolated and purified.Its activity and digestion were studied.In order to provide more data for the poteetial value of Proanthocyanidins,the main contents of the research are as follows:1.Optimization of extraction process of proanthocyanidins from chestnut shell:Taking the proanthocyanidins yield as an index,the effect of four single factors on the extraction process of the proanthocyanidins was explored.On the basis of single factor experiments,the response surface was designed using Design Expert software.the optimum extraction conditions were:extraction time 90 min,ethanol concentration70%,solid-liquid ratio 1:15?g/mL?,extraction temperature 65?,and the proanthocyanidins the rate was 2.57%and the purity was 50.21%.2.Purification and identification of Proanthocyanidins:According to the polarity of Proanthocyanidins with different degree of polymerization,the crude extracts of chestnut shell Proanthocyanidins were separated by the degree of polymerization and its structure was identified.The proanthocyanidins crude extract?named F1?was obtained from the chestnut shells under the best extraction conditions.F1 was purified by AB-8 macroporous resin,and the fractions eluted with 50%ethanol-water solution were collected to obtain the purified?named F2?.The aqueous F2 solution was extracted with petroleum ether,dichloromethane and ethyl acetate successively to collect acetic acid Ethyl ester layer portion?named F3?and aqueous layer portion?named F4?.Then these part were measured for average degree of polymerization and were analyzed by ultraviolet spectroscopy,infrared spectroscopy,high performance liquid chromatography and mass spectrometry.It was inferred that the average degree of polymerization was from small to large F3<F2<F4<F1.The absorbance peak of proanthocyanidins from chestnut shell was at 280 nm.The infrared spectrum proved that proanthocyanins was the main structural unit of proanthocyanidins.High performance liquid chromatography showed that the chestnut shell contained monomeric and gallicacid.The chestnut shell contained monomeric and dimeric Proanthocyanidins by high resolution mass spectrometry.3.Study on the activity of procyanidins:The oxidation activity and antiba cterial activity of different samples F1,F2,F3 and F4 were studied.The expe rimental results showed that:Proanthocyanidins oxidative activity better than vitamin C.And the smaller the degree of polymerization,the higher the activity.F3 has the best antioxidant capacity.Procyanidins had antibacterial activity against staphylococcus aureus.And the antibacterial activity was related to the degree of polymerization of procyanidins.The lower the degree of polymerization,the best antibacterial effect.That is,the best antibacterial concentration of ethyl acetate layer F3.4.Study on the stability of Proanthocyanidins:Considering the effects of metal ions,temperature,light,and pH on the stability of the proanthocyanidins.The stability of proanthocyanidins was determined by using the preservation ratio of procyanidins.The results showed that:Procyanidins produced a large amount of black flocs under Fe³⁺,Fe²⁺,and Ba²⁺conditions and a small amount of flocs under Cr³⁺,Zn²⁺,Sn²⁺,and Ca²⁺conditions.There was no change under K⁺,Na⁺,Al³⁺,and Mg²⁺conditions.When the temperature is greater than 60°C,procyanidins are unstable.Procyanidins are unstable to light and should be stored in the dark.However,when the pH is greater than 8,the color of the procyanidins solution changes,indicating that the stability of the procy anidins is destroyed.5.Proanthocyanidins in vitro digestion experiment:In vitro simulation of the human oral,gastrointestinal and intestinal digestive environment,the variability of procyanidins in humoan digestion was studied.Taking the proanthocyanidins yield as an index.The results showed that:Structure of pocyanidins was not destroyed in the oral cavity.Proanthocyanidins reached maximum digestibility after 120 min gastric juice,with a digestible percentage of 18.7%.In intestinal digestive environment,Proanthocyanidins reached maximum digestibility after 90 min,with a digestible percentage of 20.5%.